How to wire a Battle Switch for forward reverse of a motor?

I am having a problem with getting this switch to run a motor in forward and reverse. The wiring diagram is in the picture, but i will describe it here also. There are three leads (s1 for +, s2 for motor -, and s3 for battery -). For the s1 the same positive lead is attached to the motor and this pin, leading to the problem that if I use two to fun the motor each way then there is a constant open connection to the battery. The only way I can think of to fix this is a diode to keep the flow from going up the way it is not supposed to. If you have any other ideas or if this is not warranted I would like to know, these are expensive switches and i would hate to burn one out on a stupid mistake. Thanks in advance.